Automatic balancing device for centrifugal pumps, turbines, and the like.



P. A. GRIE'SSMANN. AUTOMATIC BALANCING DEVICE FOR,.GENTRIFUGAL PUMPS, TURBINES, AND THE LIKE.

Patented 'May 7, 1912.

APPLICATION FILED SEPT. 2B, N11.

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UNITEDv sTATus PATENT orme.'

FRANZARNO GRIESSIVIANN, OF BERLIN, GERMANY, ASSIGNOR TO THOMAS P.' KINGS- FQRD AND VIRGINIA K. HIGGINS, F 'OSWEGQ NEW YORK.

AIITQMATIC IALANGING DEVICE FOI? y l CENTRIFUGALPUMPS, TUBBINES, AND THE LIKE.

" ratfeaeeu'nay 7, 1912.

Application filed September 28, 1911. Serial No. 651,783."

To all whom t may concern: y Be it known that I, FRANZ ARNO Gruess- MANN, a subject of the Emperor of Germany, residing at Berlin, Germany, have invented .certain new and useful Improve ments inAutolnatic Balancing Devices for- Centrifugal Pumps, Turbines, and-"the Like:

and I do hereby declare the ollovvingto be a full, clear, and exact description of the invention, such as will enable others skilled in the art to which it appertains Ato make and use the same.

This invention relates to certain improvements in automatic balancing devices' for pumps, turbines, blowers and the like; and

the objects and nature of my invention will be readily understood by those skilled in the' art in the light offthe following explanation of ,the `accompanying drawings illustrating what I now consider to .be my referred embodiment from among other ormations and arrangements within the spiritV and scope of my invention.

The invention consists 1n certain novel features in construction and' in combinations and' arrangements as more fully and I particularly pointed out hereinafter.

- The accompanying drawings show in section a portion of a pump embodying my invention.

In the drawings, 1, isthe rotary pump .i shaft carrying suitable rotary members,

i l impellers.

Vfsuch as impellers 2, inclosed by and rotatable within any suitable casing 3. y

1 It is the object of the invention to p rovide simple, durable, readily accessible ineans'for automatically balancing or equalizing thel end thrust of the pump shaft and To this end, I fix a balancing member, such as piston l0, preferably on the outer (pump discharge or pressure) end v, portion of the pump shaft to both rot-ate.

and move axially therewith, and provide a4 .liquid passage from the interior or pressure `outlet around and arranged transversely.

chamber of the pump, extending exteriorly of said. piston to the outer 'face thereof and therefrom to any suitable discharge. This V.coinprises a tbrottling tissure or (radially or diagonally) of the axis ot rotation, and a' pressure chamber at the outer 'end :tace of the piston from which saidoutlet opens 'a being annular. and of* reducedldi;

ameter with .respect tothe piston andbe ing automatically increased and diminished 'in capacity by the longitudinal movement of the piston and shaft to reduce or increase vthe pressure in said chamber'.

The equalizing or 'balancing piston 10, is

vhoused and movable in a fixed cylinderl or cylindrical wall 30, -rigid with the pump casing and at its innerend open to the pump (or inner pressure) chamber @containing liquid under pressure due to the action of the pump impellerl thereon. The inner end fa e ot the piston l0, is hence constantly e posed to the pressure of said liquid. At the outer end of said'cylinder 30, I provide annular outer pressure chamber b, :the inner end wall `of which is formed by the outer end face of the piston 10. The )ist'on ll0, is -interposed in the cylinder betwf'feen the chambers@ and b, but the'exlterior diameter of the piston i's slightly reduced with respect to the interior diameter ofthe cylin der 30, to provide the narrowcontractcd or restricted annular water passage or sealing-` fissure c, for constant flow or leakage "of liquid under pressure between the adjacent concentric surfaces of piston 10, and cylinder 30, and 'fromcchamber o, to the outer or circumferential ortion of chamber fo. The fissure c, is o vconstant orl lixed`ca pacity, although restricted.

The outer end wall of the chamber b is formed by the outer end head 31, of the pump casing. This head 31 is preferably removably secured .to the pumpr casing by suitable means such as' bolts 32, and at its central portion is' so formed as to provide a liquid passage d, around the pump shaft open to any suitable r'liquid discharge e. The discharge lc, can open'to atmospl'iere, or to any suitable point or( means for taking care of the leakage through the throttling fissure. The li uid chamber or )assaoe d.

rflat edge' or portion of the outer .end piston i ace'near the center of the-piston, anda cor-' responding annularstationary edge or tacey fixed to or rigid with the casing head 31 so that said opposing rparallel-faces forming the walls ot' the outlet recede from and approach each other as the pump shaft moves longitudinally and hence increase or di` minish the capacity of said throttle outlet. If the pump shaft moves to the left, the capafity ofthe outlet is increased and hence the' pressure in chalnber Z), is reduced'below :sol

the pressure in chamberc, by the increased liowof liquid therefrom to chamber or passage d. The excess of pressure in chamber a, then tends' to force the piston (and pump shaft) to the right to counteract the thrust and restore the shaft to normal position. This movement to the right contracts the outlet f, to increase the pressurein chamber t), to approximately that in chamber a. If the shaft moves beyond normal lposition toward the right, the throttle outlet will be abnormally contracted or closed and the pressure in chamber will be increased to resist undue movement of the shaft toward the right and to tend to cause movement thereof to normal position. The parts are so arranged and proportioned as to tend to automatically maintain the piston and shaft in normal, balanced or intermediate position with the pressures in chambers a and b, about equal. l

In the specific example illustrated, I show the inner peripheral or horizontal wallv of the chamber I), and the fixed wall of the throttle outlet formed by a removable tianged ring or sleeve 4, secured to the casing head 3l. The internal diameter' of this ring is slightly reater than the diameter of the 'pump sha t, arranged concentrically therein, to provide the internal fluid passage d, around the shaft, while the inner 'end edge 40 of the ring fbims the fixed wall of the throttle outlet and is ar anged closely adjacent to theopposing vertical face of the balancing piston, and the chamber I), surrounds the ring. 'lhe ring lits concentrically within the center opening of the casing head 3l, and is formed with an exterior radial [lange 41in the chamber t), and fitting ythe inner side face of said head. 'lhe ring is suitably secured to said head, as by screws or bolts l2. extending through said llange AIl-l, into the head.

'l'ho surfaces ot. lthe piston and ring forming` the walls ol the throttle outlet are subject to wear and friction and hencer advantages are attained by arranging said surfaces ast-.lose as possible to the pump shaft` that is` by forming said surfaces ot' a small diameter with respect to the diameter oi the, piston \\'hereby the area and peripheral speed ol' said surfaces can be greatly reduced, and the friction thereot' or load imposed thereby'on the pump sha t't is reduced to the mininnuu,

Advantages are also attained by pro` viding the removable or renewable ring 4, to sustain thewear and tear of the throttle outlet forming walls and whereby said wear can be taken up, andrhence material advantages in manufact-ure and operation are gained by arrangingI this ring at the outer end face of the piston so as to be readily accessible on the removal of the casing or bearing head 31, without necessitating removal of the piston or disturbance ofthe adjustment thereof with respect to the shaft. By this arrangement, the easing or bearing head can be removed and a new ring can be readily substituted for a'worn out ring, or the worn ring can be easily and quickly adjusted to take up wear by manipulation of the ring fastening screws and the location of liners behind the ring, or otherwise. Access can be easily had to the ring for properly adjusting the same both in process of assembling in nlanufacture and when the pump is in operation.

It is usually desirable that the ring bc accurately adjusted with respect to the piston to attain the desired balancing efiiciency, and hence it is highly desirable that means be provided whereby access to t-he ring can be had by a minimum expenditure of time and labor. The ring is subjected tp cooling liquid both externally and internally and presents but a comparatively narrow edge and slight surface area to the wear of the adjacent face of the rotating piston and interposed gritl The wear on the ring tends lto reduce the length thereof and hence the ring is comparatively long lived as in the example illustrated, the ring is clongated or in the form of a sleeve, and therefore is capable of considerable longitudinal adjustment to take up wear.

In centrifugal pumps the thrust is primarily always toward' the suction end, but the balancing piston is introduced to overcome and possibly over-balance the normal thrust toward the suction end of the pump. The area of the inner .face of this piston constantly exposed to the discharge pressure in chamber (1, is preferably in excess of the area of any impeller balancing ring, that is, the area exposed to the suction pressure, so that the suction pressure is thereby overbalanced, bile the throttling fissure and pressure chamber at the outer face of the pump are depended on to automatically maintain proper balance notwithstanding the overbalaneing of the rotor toward the pressure end ofthe pump when the inner face only of the piston is considered. The length of the'piston must also be considered in connection with the number of stages employed and the packing width thereof. A

It. is evident' that various changes ami modifications might be resorted to in the forms, constructions, and arrangements of parts described without departing from the spirit and scope of my invention, and hence l do not Wish to limit myself to the exact disclosure hereof.

' Desiring to protect my invention'in the broadest manner legally possible, What I claim is:

1. ln combination, in a centrifugal pump, turbine, or the like, a rotor, a casmg therefor comprising a cylinder at its inner end constantly' open to the pump pressure and at its outer end having a removable head, a balancing piston rotating and longitudinally movable with said rotor and in said cylinder, said piston and cylinder forming a pressure chamber between they outer end face of the piston and said removable head and a sealing fissure of constane capacity for the dow of liquid under pump pressure from the inner end of said cylinder to said pressure chamber., the inner end face of said piston being constantly and freely exposed to the pump pressure and longitudinally overbalancing the rotor in a direction to carry thepiston toward said head, said pressure" chamber provided with an annular throttling outlet concentric4 With and discharging inwardly toward the rotor axis and of reduced diameter with respect to the piston and controlled by the longitudinal movement thereof to vary the pressure in said chamber, said throttling outlet being arranged between said head and thev outer end fae of the piston and comprising a removable ring forming one Wall of the outlet and accessible on the removal of said head.

2. Means for automatically balancing the end thrust of the shafts of rotors comprising a casing provided with a-removable end head-,a balancing piston rot-ating and longitudinally movablel with said shaft and forming an, annular pressure chamber be tween its outer end face and said head, and a sealing fissure of constant capacity for constant uniform ow of liquid to said chamber, said piston longitudinally overbalancing said rotor in a direction to con stantly tend to move saidpiston toward said bead and against the pressure in said chamber, the central portion of the outer end face of saidpiston and said head being provided with opposing annular walls concentric with and ,surrounding said shaft andl of reduced diameter with respect to said piston and surrounded by said chamber and forming a throttling outlet discharging inwardly from said chamber toward said shaft, one of said walls formed by a separate ring removably secured to and carried byand removable *with said head independently of and Without disturbing said shaft and saidpiston.

3. In combination, a rotary shaft subiecte'd to end thrust, a piston-fixed thereon,

y a casing therefor forming a pressure cham'- ber at the outer face of the piston and provided with a removable head forming the outer side wall of said chamber, a stationary ring having its inner face adjacent to the outer face 'of said piston to coperate therewith in forming an automatically throttling outlet opening inwardly from said chamber, said ring surrounding said shaft and at its inner surface spaced therefrom to form a discharge passage from said outlet, said ring forming the center Wall ofsaid chamber and separating the same from said passage and provided with an exterior flange, and means removably securing the ring to the head through the medium of said flange.

4. In combination, a rotary shaft subjected' to end thrust, a piston fixed thereon,

a casing therefor forming a pressure chamber at the outer face of the piston and provided With a removable end head having an enlarged center opening around said shaft, and a stationary ring having its inner edge adjacent to the outer face of said piston to coperate therewith in forming an automatically throttling outlet opening in- Wardly from said chamber to a liquid olft-ake-passage around said shaft and Within said opening of said head, said ring being fitted Within said center opening of said head and being carried byand removably secured to said head and at its inner surface forming the outer Wall of said passage.

5.*111 combination, a rotary shaft subjected to endthrust, a balancing piston fixed thereon, a casing forming pressurechambers at the faces of ,said piston, and a stationary ring carried by and'removably fixed to said casing concentric with said shaft and of reduced diameter With respect to said piston and presenting an end edge adj acent to the central portion of a faceof said piston to coperate therewith in forming an automatically throttling pressure agent passage, means being provided Whereby said ring is adjustable independently of said casing and piston and longitudinally of said shaft whereby Wear can be taken up Without disturbing the piston adjustment.

'6. Means for automaticallybalancing the end thrust of'shafts df pumps andthe like,

comprising-a balancing piston on tle pump shaft and hav-ing :in inner face of fixed area constantly and freely exposed to the pump discharge pressure to ov'erbalance thrust'tovvard the suction end of the pump, i

,tling outlet controlled by the axial Inovement of said piston for varying the pressure at said outer face to counteract thrust toward the pressure end of the pump.

7. Means for automatically balanclng the end thrust of rotors of centrifugal/pumpsand the like, comprisingva'bal'ancing piston on the pump shaft and having iis inner face constantly and freely exposed throughout its areafco the pump discharge pressure and of an area. to Overbnhmce thrust toward the suction end of the pump and set up normal thrust toward the pressure end of the pumpb and means providing u liquid passage from the pump discharge to the outer piston face comprising mseuliug iissure al; the periphery of the piston e011- stantly open to the pump discharge pressure for the iow of liquid under said discharge l i l FRANZ ARNO GRIESSMANN.

Witnesses HENRY HASPER, ARTHUR SGHROEDER. 

